Water is the main running substance for wet processing in the textile industry as well as other manufacturing industry. The water is in an environment that contains lots of impurities which require for purifying before use. Through purification, natural water becomes suitable for the process.
Water Source In Textile Industry
Water for a textile plant may come from various sources. These include surface water from rivers and lakes and subterranean water from wells. In most of the textile industries, they collect water from the Underground. Natural and pretreated water may contain a variety of chemical species that can influence textile wet processing in general and dyeing in particular.
Types of Water Hardness
The various salts present in water depend on the geological formations through which the water has flowed. These salts are mainly the carbonates (CO32-), hydrogen carbonates or bi-carbonates (HCO3-), Sulphates (SO42-), and chlorides (Cl-) of calcium (Ca2+), and magnesium (Mg2+). Although calcium and magnesium carbonates in limestone are relatively insoluble in water. So for these reasons, water hardness divides into two ways. They are-
If the water contains Ca(HCO3)2, Mg(HCO3)2, and Fe(HCO3)2 then it is called temporary hardness.
If the water contains CaCl2, CaSO4, Ca (NO3)2, MgCl2, MgSO4, and Mg (NO3)2 then it is called permanent hardness.
Effect of Hard Water in the Textile Industry:
This water hardness causes some serious consequences in the textile dyeing and finishing industries and these are
- Firstly, precipitation of soaps.
- Secondly, redeposit ion of dirt and insoluble soaps on the yarn or fabrics being washed, this can cause yellowing and lead to uneven dyeing and poor handle.
- Thirdly, precipitation of some dyes as calcium and magnesium salts.
- After that, scale formation on equipment and in boilers and pipelines.
- Lastly, incompatibility with chemicals in finishing recipes and so on.
In sum, water hardness is expressed by parts per million (ppm) of CaCO3 which is the standard hardness scale and is also called American hardness. The hardness of raw water is 100 ppm or more. To use it in dyeing and boiler, this water must need to soft & foreign materials needs to remove.